SDET vs. QA Tester: Key Differences and Similarities

David Borcherding

January 10, 2024

In a previous article, we briefly touched on the differences between the QA tester role and that of a software development engineer in test (SDET).

While there is some overlap in expertise and responsibilities, the two jobs are significantly different. 

QA testers focus on performing manual and automated tests on recently developed or updated software before it gets released. They may have some knowledge of coding, but their skills are not as expansive as a software developer’s.

SDETs are software developers with a full range of coding skills. They focus entirely on testing but have the knowledge and experience to write code and develop features. 

This article takes a more in-depth look at the differences between these two software quality assurance roles.

What is a QA Tester?

QA tester, QA analyst, and QA engineer are all similar roles, and the titles are sometimes used interchangeably. 

Some use experience to differentiate between the three. QA testers are entry-level roles who get promoted to QA analysts over time and eventually move up to QA engineers.

Others define the three roles by their responsibilities: 

  • QA testers are given a list of test cases. They perform the tests and record the results. 
  • QA analysts also perform tests but also design test cases. They’re expected to know how to plan tests, not just execute them. 
  • QA engineers have all the responsibilities and skills of an analyst, along with some knowledge of coding and developing automated tests, either by contributing to a framework or creating one. 

In this hierarchy, all roles perform manual testing to some degree. QA testers may perform the bulk of it, but QA analysts and engineers still do some of it. Hence, the lines between the three blur a bit.

Depending on the organization, QA testers may be required to handle the following tasks:

  • Test project supervision
  • Test suite builds
  • Automated test configuration
  • Manual and automated test execution
  • Test environment management

In addition, a QA tester may review user stories, develop manual and automated functional tests based on story features, and then build the appropriate set of tests, including: 

  • Smoke tests
  • Feature tests
  • Functional tests
  • Integration tests
  • Regression tests 

QA testers execute the required tests, entering defects they discover in a bug-tracking tool such as Jira or Helix. Testers may also be responsible for configuring test environments for new feature releases or development cycles.

And, of course, there’s reporting. QA testers document all test processes and report the results of each testing cycle. 

How are SDETs different?

Although SDETs often sit with the QA testers (hence the “in test” part of their title), they don’t perform tests. Instead, SDETs focus almost entirely on creating the framework, planning, and supporting automated tests. 

SDETs have in-depth programming or development knowledge (hence the “software development engineer” part of their title). They combine their development experience with an understanding of how to design and develop both manual and automated tests.

SDETs collaborate with QAs and developers throughout the SDLC, from beginning to end. They review code, participate in code reviews, and have a fundamental understanding of software development concepts.

Depending on the organization, SDETs are responsible for the following tasks:

  • Planning and managing the test automation framework 
  • Managing the required tools
  • Managing the unit test process
  • Designing, developing, and supporting automated tests
  • Analyzing debugging and failed test 
  • Aligning test suites with specific code builds
  • Scripting tests related to CI/CD

In addition to providing code support for test automation, SDETs are often tasked with developing automated tests for security, application performance, and unit testing. They also play a vital role in improving software by helping developers debug features and participating in code reviews.

How are SDETs and QA Testers similar?

SDETs and QA testers share some common ground, as they both play crucial roles in ensuring the quality and functionality of software. 

Both SDETs and QA testers are quality advocates, working to uncover defects and prevent them from reaching production. They strive to improve the overall software quality by reporting issues and suggesting improvements. Their ultimate objective is to deliver a polished, bug-free software product to the end users.

As a result, the two roles have overlapping skills:

  • Analytical thinking: Both SDETs and QA testers need strong analytical skills to identify patterns, analyze test results, and draw meaningful conclusions from data.
  • Attention to detail: A keen eye for detail is crucial for both roles, as even minor defects can significantly impact the user experience.
  • Problem-solving: Both SDETs and QA testers need to be adept at problem-solving to identify the root cause of bugs and devise effective solutions.
  • Communication: Clear and concise communication is essential for both roles, as they need to collaborate with developers, designers, and other stakeholders to report bugs and suggest improvements effectively.

The nature of their work is highly collaborative, leveraging their respective strengths to achieve optimal testing coverage. SDETs develop automated test scripts, while QA testers execute them and perform manual testing to identify edge cases.

Both roles benefit from a good understanding of the SDLC and testing methodologies. This shared knowledge base fosters better collaboration and ensures a more efficient testing process.

Are SDETs necessary for QA?

Depending on the level of test automation knowledge already present, a QA team may not need a dedicated SDET. However, adding an SDET to a QA team can help create more comprehensive test coverage.

This can be particularly beneficial for Agile teams working in highly regulated environments. These industries mandate heavy amounts of validation and verification, some of which may need to be automated. 

In such cases, SDETs can help development teams increase test automation and provide support for complex test procedures.

However, some organizations do combine the QA tester and SDET roles. Well, they try. While this approach can be made to work, it’s not ideal. The reason is that each role’s responsibilities require significant work and focus on different levels of test coverage. Putting it all on one person’s shoulders often results in less efficiency than keeping the roles separate.

Complementary Roles

While QA testers and SDETs are very different roles, they work exceptionally well together to improve software product quality. Both roles help increase the focus on testing and provide expanded test coverage.

Through their combined efforts, SDETs and QA testers are able to catch more defects before product release.